Electrotherapeutic apparatus with body impedance-sensitive intensity regulation



3,489,152 SENSITIVE Jan. 13,1970 1.. J. BARBARA ELECTROTHERAPEUTIC APPARATUS WITH BODY IMPEDANCE INTENSITY REGULATION 2 Sheets-Sheet 1 Filed April 18, 1967 $6 0104; ywmm 5mm 31:: F7; TER

INVENTOR lay/5 JF4F54P4 Jan. 13, 1970 J. BARBARA 3,489.152

ELECTROTHERAPEUTIC APPA RATUS WITH BODY IMPEDANCE-SENSITIVE INTENSITY REGULATION Filed April 18, 196'? 2 Sheets-Sheet 2 United States Patent ELECTROTHERAPEUTIC APPARATUS WITH BODY IMPEDANCE-SENSITIVE INTENSITY REGULATION Louis J. Barbara, 222 77th St., Miami Beach, Fla. 33141 Filed Apr. 18, 1967, Ser. No. 631,636 Int. Cl. A61n 1/00, 1/08 US. Cl. 128422 5 Claims ABSTRACT OF THE DISCLOSURE An electrotherapeutic device embodying means for generating random, infrasonic and other varying signals, amplifying said signals, and applying the amplified signals to the human body for diagnostic and therapeutic purposes. The intensity of the applied signals is controlled by means responsive to changes in the impedance of the patients body.

This invention relates to electrotherapy and more specifically to a method and system for generating low intensity currents and appplying them to the body for diagnostic and therapeutic purposes.

The direct or galvanic currents are primarily for electrolytic treatment of body tissues by effecting more rapid and positive introduction of drugs and medicines into the body while the alternating and interrupted currents have been used for the diagnosis of neuromuscular disorders. In electrodiagnosis of this character, it is essential that the desired effects be produced with the minimum current and of course minimum discomfort to the patient. While some success has been achieved in electrodiagnostic methods of this character, the instability, unpredictable patient response, the possibility of severe nerve damage because of uncontrollable conditions and the severely limited usefulness of such equipment has led physicians to avoid its general use and rely on other alternative procedures.

It has been found that neuromuscular responses to electric currents vary with the character of such current and that properly generated currents can be used not only to diagnose neuromuscular disorders but also for therapeutic purposes while at the same time providing a simplified and rapid treatment in a completely safe manner. Accordingly, one object of the invention resides in the provision of low current therapeutic apparatus for generating purely random current variations that will produce more effective nerve stimulations without the danger encountered in the utilization of currents of the order of 50 to 100 milliamperes heretofore employed. Tests have indicated that if subliminal stimuli that normally of themselves would not produce a response, when these stimuli follow each other within a certain time a response is obtained. The most effective rate of such stimuli has been found to be in the range of infrasonic frequencies and generally of the order of 7 to 15 cycles per second with both the amplitude and occurrence being at a random rate in which case excellent stimulation is provided with currents of the order of 5 or 6 milliamperes or less. Thus if desired deep seated nerves can be stimulated without damaging the shallower nerves and without material patient discomfort. It therefore follows that this improved nerve stimulating apparatus and procedure opens avenues of therapy not heretofore available and that are of particular advantage to endocrinologists in correcting glandular disorders that very often form the basic cause of other more serious diseases.

Another important factor in the use of electric currents for the stimulation of nerves resides in the coupling between the generator and the nerves to be treated. Con- 3,489,152 Patented Jan. 13, 1970 ventional impedance and capacity coupling while effecting certain results have not afforded satisfactory current regulation because of substantially instantaneous metabolic changes of the body and resultant impedance variations. Since the body resistance or impedance is effectively in series with the generator, the current through the body will vary inversely with the body resistance. Another object of the invention therefore is to provide improved coupling means between an electric signal generator and the body that will instantaneously regulate the applied voltage in accordance with metabolic changes thus assuring stimulation at a predetermined level.

Still another object of the invention resides in the provision of electrotherapeutic apparatus for generating random stimuli for the stimulation of nerves wherein the intensity of the stimulating currents may be carefully and accurately controlled and wherein the amplitude range of the random pulses may be varied within predetermined limits.

A still further object of the invention resides in the provision of an improved method and apparatus for introducing electrical stimuli into the body for the stimulation of deep seated nerves without utilizing currents of a magnitude that will cause discomfort to the patient or adversely affecting those nerves closer to the surface of the body. Thus direct nerve stimulation is attained more safely and positively and the usefulness of electric energy for therapeutic purposes is greatly enhanced.

A further object of the invention is the provision of electrotherapeutic apparatus wherein two or more nerve stimulating currents may be simultaneously introduced into the body in like or different phases to effect beneficial results not attainable with prior apparatus.

Still another object of the invention resides in a new and improved electrotherapeutic apparatus and method of application of the stimuli produced thereby to the body.

The above and other objects and advantages of this invention will become more apparent from the following description and accompanying drawings forming part of this application.

In the drawings:

FIGURE 1 is a diagram of one embodiment of the invention with part thereof in block form and part thereof in circuit form.

FIGURE 2 is a circuit diagram of one form of signal generator in accordance with the invention.

FIGURE 3 is a modified form of a random signal generator useful in connection with the circuit shown in FIGURE 2.

FIGURE 4 is a diagram of still another embodiment of the invention for generating modulated nerve stimulation signals.

FIGURE 5 is a circuit diagram of still another embodiment of the invention, and

FIGURE 6 is a circuit diagram of still another embodiment of the invention.

Broadly, this invention contemplates the provision of an improved method and apparatus for the stimulation of nerves and utilizes signals of random frequency and amplitude that have been found to provide more effective diagnostic and therapeutic results with less discomfort to the patient. Moreover, because of the basic characteristic of the body structure these frequencies may be impressed on a higher frequency signal that will penetrate the body and be demodulated more effectively upon arrival at a nerve or nerves to be activated in the deeper tissue so that the random frequency will actuate or stimulate the nerves in the usual manner. This procedure enables the stimulation of deep seated nerves with negligible current thus avoiding considerable discomfort on the part of the patient as well as adverse effects on nerves that are closer to the body surface. In addition, means are provided for insuring uniform transmission of energy into the body notwithstanding ing metabolic changes which constantly vary the body impedance. One embodiment of the invention for the attainment of these ends is illustrated in FIGURE 1.

In this figure, denotes a signal generator adapted to produce a signal composed of random frequencies at random intensities. Such a signal generator preferably comprises a suitable noise source such as that obtained through the medium of a gaseous electronic tube that will be described in greater detail as the description proceeds.

The output of this signal generator is fed to an adjustable filter 11 so that different frequency groups preferably in the vicinity of the infrasonic range may be selected as required. One frequency group that has been found to be particularly effective in the stimulation of nerves is the range of 7 to cycles per second though good results are obtainable with frequencies as low as one-half cycle per second. It will be observed that inasmuch as this group of frequencies is selected from a source of randomly varying energy that the occurrence of the several frequencies within this group and their amplitude will be entirely random.

The output of the band pass filter 11 is fed through a conventional amplifier 12 to increase the signal level. If desired, a feedback network 13 shown in dotted out line may be connected about the amplifier 12 in order to provide a controlled output signal in the manner Wellknown in the art. The output of the amplifier 12 is coupled through a condenser 14 to a vacuum tube 15 connected as a cathode follower for impression of the signal between two points of the body. More specifically, the plate 16 of this cathode follower is connected to a regulated source of potential, while the cathode 17 is connected through a pair of resistors 18 and 19 to ground. The grid 20 is coupled to the condenser 14 and through a grid return resistor 21 to the junction of the cathode resistors 18 and 19. The output from the cathode follower cathode 17 is taken off through a condenser 22 and applied to one side of a potentiometer 23. The adjustable tap 24 of the potentiometer is connected to a positive electrode terminal 25 while the negative electrode 26 is connected to ground as illustrated.

It will be observed that in the use of the cathode follower in this manner as the body impedance changes it will reflect a change in the load on the cathode follower between the cathode 17 and ground since the load circuit for the tube 15 includes all the elements between the cathode 17 and ground. This change in body resistance as a result of metabolic changes will reflect a corresponding change in the AC potential of the cathode 17. If the increase is in a positive direction, the cathod load willincrease in impedance with the result that the cathode becomes more positive. This reacts on the operation of the tube 15 by effectively increasing the grid bias or the negative potential between the grid 20 and the cathode 17. This decreases in the plate current through the cathode load and tends to maintain the voltage across the potentiometer and hence the voltage between the terminals 25 and 26 at a constant level. The nature of this regulatory action is substantially instantaneous and can be controlled by relative values of the cathode resistors 18 and 19 since the cathode resistor 18 determines the bias on the tube and the resistor 19 merely constitutes a load resistor for attaining an increased signal across the potentiometer 23. In addition, the maximum current through the body is limited by the maximum output available from the tube before saturation.

FIGURE 2 illustrates one form of a signal generator and band pass filter corresponding to the elements 10 and 11 of FIGURE 1. This circuit also includes means for controlling the range of random amplitude desired in the stimulating signalfi More specifically, the random signal generator includes a gaseous tube 27 connected as a diode with the grids 28 and 29 coupled directly to the cathode 20 which in turn is connected to ground. The plate 31 is connected through a resistor 32 to a source of positive potential as illustrated. The application of a potential across this diode will produce a randomly varying signal having sub-sonic, sonic and super-sonic frequencies at the plate 31 and this signal is fed through a condenser 33 to the grid 34 of an amplifier tube 35. The grid is returned to ground through a resistor 36. The cathode 37 of the tube is connected to ground through a parallel connected resistor 38 and condenser 39 while the plate 40 is coupled through a resistor 41 to a source of positive potential. The plate circuit of the tube 35 includes a filter comprising a resistor 42 and a condenser 43 between the plate and ground for attenuating the high frequencies and forms a portion of a band pass filter 11 as shown in FIG- URE 1. The junction resistor 42 and condenser 43 is fed through a coupling condenser 44 to the grid 45 of a second amplifier tube 46. This tube has its cathode 47 connected to ground through a resistor 48 and condenser 49 and its plate 50 is connected through a resistor 51 to a source of positive potential. The output circuit from the plate 50 of the tube 46 includes a pair of condensers 52 and 53 connected in series between the plate 50 and ground and the junction of these condensers is fed through an adjustable potentiometer 54 and a series resistor 55 to ground. This arrangement will maintain the response of the tube 46 in the center of a desired band of frequencies determined by the value of the condensers 43, 52, 53, and 63 and associated resistors. The condensers 43 and 53 serve to bypass the higher frequencies While condensers 33, 44, 52, and 63 tend to attenuate the lower frequencies. In this way good filtering action can be attained to limit the range of frequencies to any desired band in the infrasonic range.

The output of the noise generator and filter thus far described is fed from a slidable contact on a potentiometer 54 to the grid 56 of the amplifier tube 57. This tube has its cathode 58 connected to ground through the resistor 59 and condenser 60 while the plate 61 is connected through a resistor 62 to a source of positive potential. The tube 57 is preferably arranged to operate as a so-called clipper or compressor and this is accomplished by applying a very low positive voltage to the resistor 62 so that a very small signal applied to the grids 56 will cause the tube to reach a maximum plate current point and thus limit the output signal from the plate 61. The output of this clipper is fed through a condenser 63 to a potentiometer 64, and a slidable contactor on this potentiometer is fed to the grid 65 of a tube 66 connected as a conventional amplifier with the output being obtained from the plate 67 through a condenser 68. The potentiometers 54 and 64 are preferably mechanically coupled one to the other and are arranged to be simultaneously operated in reverse directions by a single control knob. In this way the output appearing at the condenser 68 will remain substantially constant for all adjustments. For example, as the potentiometer 54 is adjusted to provide increased signal on the tube 57, the potentiometer 64 is decreased to reduce the signal applied to the grid 65 of the tube 66. Thus the output amplitude is maintained constant but the average variation in random amplitude is reduced. Similarly as the potentiometer 54 is adjusted to reduce the signal level to the tube 67, the potentiometer 64 simultaneously increases the signal level to the tube 66. This reduces the amount of clipping and enables a relatively wide range of amplitudes to be obtained in the output signal. This procedure has been found to be effective in regulating nerve stimulation since random peak pulses can be varied in intensity depending on specific requirements. If desired the band pass filters used in connection with tubes 35 and 46 can be of course be made adjustable nature so that the range in frequencies also can be selected at will.

An alternate noise generator that may be used in place of the tube 27 is shown in FIGURE 3. Here a gaseous voltage regulator tube 69 is connected in series with a resistor 70 and across a suitable supply of positive potential and the output signal is obtained from the junction of the resistor 70 and the tube 69 through a coupling condenser 71 for the purpose of blocking the direct current applied to the tube.

An alternate embodiment of the invention is shown in FIGURE 4 and includes a signal generator 10, a band pass filter 11 and an amplifier 12 as described in connection with FIGURES 1 and 2. The output of the amplifier 12, however, is fed in this instance to a modulator 72 that is interconnected with a suitable oscillator 73. The oscillator signal after modulation by the random frequencies attained from amplifier 12 is fed through a coupling condenser 14 to the cathode follower output tube which functions precisely as the tube 15 of FIGURE 1 and like numerals have been applied to like elements of each figure. The oscillator 73 is preferably arranged to produce a signal upwardly of 8,000 to 10,000 cycles per second and may even be in the super-sonic range. With this arrange ment, it has been found that the modulated signal fed into the body will be rectified or demodulated and thus effect the desired nerve stimulation. Demodulation eliminates the high frequency signal and leaves only the relatively low frequency random signal to effect the desired stimulation. This procedure enables more effective transmission of the stimulating source to the nerve and permits reduced currents to be used in order to effect the desired degree of stimulation. Consequently the patient experiences materially reduced discomfort and possible damage to nerves that may be closer to the surface and in the path of the stimulating pulse is avoided.

In certain applications, it is often desirable to stimulate nerves in the body with two signals simultaneously and in some cases it is desirable that these signals be in phase one with the other while in other cases it is desirable to have them out of phase. One method for the attainment of this end is illustrated in FIGURE 5. In this figure, the tube 74 operates as a phase inverter in conjunction with the tubes 75 and 76. The output signal from amplifier 12 or the modulator 72 is fed to the grid 77 of tube 74 through a resistor 78 and directly to the grid 76' of tube 76. The cathode 79 of tube 74 is connected to ground through a resistor 79' while the plate 80 is connected to a positive potential through a resistor 80". The output signal is obtained from tube 74 by condenser 81 and fed to the grid 75 of tube 75. By reason of the interposition of tube 74, the grids of tubes 75 and 76 will now be 180 out of phase. Resistors 82' and 82 return these grids to ground while the cathodes of the tubes 75 and 76 are connected to ground through the resistor 83. In order to maintain the signal levels at grids 75' and 76' uniform, a feed back resistor 84 is connected around tube 74 to decrease its gain to unity. The plates 85 and 86 of tubes 75 and 76 are connected to a positive potential through resistors 85 and 86. The cathode follower output tube 15 and associated circuit is identical to that shown in FIGURE 1 and is coupled to the plate 85 of tube 75 by a suitable blocking condenser. A second cathode follower output tube 15 is identical to the tube 15 and connected in a similar manner. Accordingly, elements in the circuit associated with the tube 15' are denoted by primed numerals corresponding to the numerals denoting the several components in the circuit associated with the tube 15. The grid of the tube 15' is connected to the movable arm 87 of a single pole double throw switch. One fixed contact 87' of this switch is to the plate 86 of tube 76 while the other fixed contact 87" is connected to the plate 85 of tube 75. With the movable element 87 of the switch on contact 87' the tube 15' receives its signals from the plate 86 of the tube 76 while the tube 15 receives its signals from the plate 80 of the tube 75. In this way the signals appearing at the terminals and 25' will be 180 out of phase. When the switch on 87 is thrown to the fixed contact 87" the grids 20 and 20' are connected in parallel to the plate of tube 75 and the outputs 25 and 25 will be in phase.

In many instances it is found to be highly desirable to enable the patient to hear the nature of the signals being fed into the body during the treatment. This may be readily accomplished by the arrangement shown in FIGURE 1 and comprises a suitable amplifier 88 preferably coupled to the output of the amplifier 12. This amplifier 88 in turn drives a loud speaker 89 adapted to reproduce the random signals used in the treatment. It is of course apparent that the amplifier 88 would be provided with suitable gain controls so that the volume of the sound emanating from the speaker 89 can be controlled at will.

FIGURE 6 illustrates another embodiment of the invention wherein other sources of signals may be employed if desired. In this figure the input terminal 90 may be connected to signal sources producing random variations suitable for this purpose as, for instance, random or repetitive sounds sometimes occurring in music. The monitor 91 may be utilized to listen to the signals being employed and may include either a set of head phones or a loud speaker, The input control device 92 may take the form of a potentiometer and a vacuum tube boltmeter 93 or its equivalent is preferably used to indicate the input level. The amplifier tubes 94, 95, and 96 are preferably voltage amplifiers for increasing the magnitude of the input signal in the conventional manner. The tube 97 which may be similar to the tubes 94 to 96, inclusive, is connected as a phase inverter to obtain two out of phase signals. If desired, any other suitable procedures may be employed for the attainment of this end. In order to stabilize the operation of the amplifier tubes 94 to 96 and provide means for compressing the output signal, a feedback circuit including a diode 98 and a pair of amplifier tubes 99 and 100 are provided and interconnected between the tube 97 and the grid of the tube 95. Compression control is effected by the compression potentimeter 101. The cathode follower output tubes 103 and 104 are connected to the output tube 97 by means of a switch 105 to produce either out of phase or in phase signals at the pads 106 and 107 with respect to a neutral pad 108. A vacuum tube voltmeter 109 may be provided between the pads 106 and 108 to provide an output level indication. In order to stabilize the operation of the amplifier, a conventional feed back circuit employing condenser 110 and a series resistor 111 may be employed between the plate of the tube 97 and the cathode of the tube 94. It is also apparent that the circuit shown in FIGURE 1 may also include means for controlling the amplitude range as well as the frequency range of the signals delivered to the pads 106 and 108 in the manner described in the previous figures.

While several embodiments of the invention have been illustrated and described for the purpose of illustrating the advantages and operation of the invention, it is apparent that other modifications, alterations and changes may be employed without departing from the true scope and spirit thereof as defined by the appended claims.

What is claimed is:

1. Electrotherapeutic apparatus comprising a signal generator, an amplifier interconnected with said generator, and means connected with said amplifier for ap plying the amplified signal to the body to be treated including an impedance variable in response to the impedance of said body to automatically regulate the signal intensity, the last said means including a phase inverter, two cathode followers and means coupling said cathode followers with said phase inverter to produce in phase and out of phase operation of said cathode followers.

2. In electrotherapeutic apparatus according to claim 1 including a filter connected with said amplifier, said filter being tunable to select a band of frequencies in the infrasonic range.

3. In electrotherapeutic apparatus according to claim 7 8 1 including means connected with said amplifier for limit wherein said signal generator produces signals in the ing amplitude variations in said amplifier to predeterrange of seven to eleven cycles per second. mined amplitude ranges while maintaining a constant maximum l L References Cited flectroltlhetrlapeutic apparatllist according got claim; 1 5 UNITED STATES PATENTS 111C u ing a 1g requency 0501 a or, a mo u a or 1n erconnected with said oscillator, and connections between 2773185 12/1955 PHI/[9n et said oscillator and amplifier for producing a modulated 2823311 2/1958 l freque cy sig al g 5. Electrotherapeutic apparatus according to claim 1 10 WILLIAM E. KAMM, Primary Examiner 

